In the past the scampi was shelled by machine in Scotland. Now it is taken first to container ports like Grangemouth and loaded into containers, which are in effect giant freezers.

They are shipped to Rotterdam before being loaded onto a huge container ship alongside around 7,000 other containers for the long haul to Bangkok.

The key part of the process takes place in Thailand, as the langoustine are peeled by hand - the way consumer research says we like our scampi.

The long journey home from Bangkok takes the frozen, peeled langoustine through Rotterdam again before a short hop across the North Sea to Grimsby, where the scampi is breaded - and then delivered to our supermarkets and our plates.

The whole round-trip is about 17,000 miles (27,353km).

So how can this make sense?

This doesn't make any sort of sense at all

Willie Mackenzie, Greenpeace

The company submitted research to the independent Carbon Trust. The conclusion was that shipping scampi to and from Thailand is no more environmentally damaging than peeling it by machine in this country.

Mike Parker, deputy CEO of Young's, says the science is on their side.

"What they found was that there was no difference between the two, and the reason for that is simply that by moving from machine processing here in the UK to hand processing in Thailand saves a lot of energy, and obviously a lot of the CO2 emissions associated with that.

"But at the same time the C02 emissions associated with shipping to Thailand and back are actually very, very low."

He insists Young's are very serious about the environmental impact of their operations, and points out, for example, that enormous effort is devoted to fish stock sustainability, aimed at ensuring natural supplies are there for the long term.

The 'Fish For Life' approach at the heart of their operations includes commitments to traceability, not sourcing illegally fished stock, and clear labelling.

After being peeled in Bangkok, the scampi is breaded in Grimsby

Set against that, asked if he can see why people may think the Thailand move was still "crazy", he says: "I can understand that perception but that perception is wrong."

But still some environmentalists say it's a classic example of food madness.

"This doesn't make any sort of sense at all," says Willie Mackenzie of Greenpeace.

"Sending shrimp half way round the world to send it back again is just nonsense.

"They cover this up and distract it by saying it's carbon neutral, but in truth this is about minimising costs and maximising profits."